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(59,579 posts)
Fri Nov 17, 2023, 09:43 AM Nov 2023

Heat Index In Rio Hits 137.3F


More than a hundred million people in Brazil endure extraordinary and lethal temperatures. The heat index, a combination of temperature and humidity, shattered records in Rio de Janeiro with 108.5 degrees and a feel-like temperature of 137.3 F. The gobsmacking temperatures are a November heat record for the sprawling city of Rio de Janeiro, which has approximately fourteen million people.

Red health alerts have been posted for thousands of cities across the nation. There was no cooling relief for the bodies of wildlife and humans during the night as temperatures hovered around 90 degrees F.

Favelas, located in the upslope of Rio, have little to no air conditioning. ’Problems with electricity in favelas are chronic and emerged along with the favelas themselves. The State fails by delivering low-quality service, and residents, improvising, end up overloading grids and making the entire favela population suffer as a result. People spend days without electricity in their homes, food and appliances are lost, and according to residents, all of this gets worse in summer.’ rioonwatch.org/...


Inmet has issued red alerts for a large part of the country. These indicate that temperatures may be 5C above average for longer than five days and could pose a serious danger to health. The heatwave, which comes more than a month before the beginning of summer in the southern hemisphere, has seen Brazil's energy consumption soar to record levels as people try to keep themselves cool. Inmet research released last week showed that the average temperature in the country had been above the historical average from July to October. Extreme weather is becoming more frequent and more intense in many places around the world because of climate change.


Poconã, Brazil — The Pantanal wetlands in western Brazil are famed as a paradise of biodiversity, but these days they have enormous clouds of smoke billowing over them, as raging wildfires reduce vast expanses to scorched earth.

Known for its lush landscapes and vibrant wildlife, including jaguars, caimans, macaws and monkeys, the Pantanal is home to the world's biggest tropical wetlands and, in normal times, a thriving ecotourism industry. But in recent weeks it has been ravaged by fires that are threatening its iconic wildlife, as Brazil suffers through a southern hemisphere spring of droughts and record heat.


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Heat Index In Rio Hits 137.3F (Original Post) hatrack Nov 2023 OP
See also OKIsItJustMe Nov 2023 #1
Heat index is useful but wet bulb orthoclad Nov 2023 #2
One advantage of "Heat Index" or "Feels Like Temperature" is that people are used to it from TV weather forecasts OKIsItJustMe Nov 2023 #3
Thanks, good resources orthoclad Nov 2023 #4


(2,910 posts)
2. Heat index is useful but wet bulb
Fri Nov 17, 2023, 12:10 PM
Nov 2023

is a better indication of the impact on living things at temperature extremes. Wet bulb temperature is what a thermometer clad in a wet cloth sees. It allows for the effect of humidity.

I wrote a thread a few months ago about wet bulb temps in Iran nudging the human-lethal point. I didn't find any reports on fatalities; I guess the mullahs kept that quiet, since their power depends on fossil fuel. But ocean temperatures in the Persian Gulf hit 100F - providing a bad combination of heat and humidity.

There's a wiki on recent wet-bulb temperature events. It omits the 2023 Iran event, which recorded a wet bulb of 33.7C at an airport. https://en.wikipedia.org/wiki/Wet-bulb_temperature
from the wiki:
"It has been thought that a sustained wet-bulb temperature exceeding 35 °C (95 °F)—given the body's requirement to maintain a core temperature of about 37°C—is likely to be fatal even to fit and healthy people, unclothed in the shade next to a fan; at this temperature human bodies switch from shedding heat to the environment, to gaining heat from it."

The elderly, sick, weak, and poor die sooner.

Some recent wet-bulb temperature events (from the wiki; more are listed):
36.3 Ras Al Khaimah City, Ras Al Khaimah UAE
36.2 Jacobabad, Sindh Pakistan
36 Mecca Saudi Arabia
35.8 Hisar, Haryana India
35.6 Yannarie, Western Australia Australia
35.4 Villahermosa, Tabasco Mexico
35.1 [unnamed location], Khyber Pakhtunkhwa Pakistan
35 Maracaibo Venezuela
35 Matlapa, San Luis Potosi Mexico
35 Choix, Sinaloa Mexico

Things are cookin'


(19,937 posts)
3. One advantage of "Heat Index" or "Feels Like Temperature" is that people are used to it from TV weather forecasts
Fri Nov 17, 2023, 01:10 PM
Nov 2023

Here’s a nice YouTube video showing how to determine “Wet Bulb” temperature. I was taught to do this in 9th Grade Earth Science:

The National Weather Service has a handy “Wet Bulb Globe Temperature Informational Guide” which is even more useful than “Wet Bulb.”

Wikipedia: Wet-bulb globe temperature


(2,910 posts)
4. Thanks, good resources
Fri Nov 17, 2023, 02:36 PM
Nov 2023

Heat index is familiar, but intended for temperature ranges which are merely uncomfortable, not dangerous.

There were US deaths last summer from people who ignored the hazards of heat, e.g. hiking in the desert. It will take some time and effort, but education to indices like the global wet bulb (which includes things like radiant heat sources) will help people, now that lethal heat is becoming more common.

Unfortunately, much of the world does not have the wealth or resources for things like air conditioning, or even fresh cool water. I worked in some extremely hot environments when I was much younger. I appreciate how dangerous that would be to me now in my dotage. I get heat cramps very easily. A significant portion of the population in regions prone to heat catastrophe will suffer greatly when conditions get even close to official danger points.

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